You admitted in your earlier post that you don't understand how xG is calculated and that shows in these posts. As I explained, xPTS is a simple calculation between xG for and against in each match. If you look back through every season in which Alisson has been at the club, we've outpeformed xGA by big amounts - we've shown therefore that this is sustainable. That means that our performance relative to xPTS is almost entirely linked to our attack - if you look back through the 5/6 seasons, when our attack has performed inline (or above) xG then our xPTS have been way above expectations, up to a huge amount when our attack has overperformed as much as Alisson has and when we've underperformed in attack our xPTS 'only' reverts to the norm. Our performances in attack this season have been bang in line with xG - that is 100% sustainable and as mentioned, outperforming xGA is exactly what we always do so again sustainable. Our points total relative to performances is exactly where it should be based on our players - this will only change (for good or bad) if the performance of our forwards change or we're without Alisson for a prolonged period.
Ha, I know exactly how xG is calculated, I just hadn't considered that is doesn't take into account the ability of the keeper. And yes, xPTS looks at the xG and simply states whichever team had the higher xG 'deserved to win' - seems another flawed metric...for example, if you didn't get more than +1 xG then is it really fair that that table gives you the 3 points? because technically you didn't do enough to beat the team by the required 1 goal (is there such a table anywhere?)
I totally understand where you're coming from now, but the fact you're hitting xG at the moment doesn't necessarily mean you will maintain it, because (as you say) you have not done so in 4 of the last 4 years, so again - is it sustainable? "able to be maintained at a certain rate or level." I'd say not (certainly not your 100%!), anything can happen in the last 13 games what with injuries etc.
By the way, this is coming from someone who has no problem with Liverpool* winning the league...in fact I said to my mate some time ago that I worried more about Liverpool than Man City this season, and I think you've got the easier run-in or all 3 - it just erks me when Arsenal get swept under the rug and the media go on about Liverpool.
*I should clarify, rather Liverpool than Man City!